Opengovsg TypeScript Library

The Opengovsg TypeScript library provides convenient access to the Opengovsg APIs from TypeScript.

Table of Contents

• Installation
• Reference
• Usage
• Request and Response Types
• Exception Handling
• Advanced
  • Additional Headers
  • Retries
  • Timeouts
  • Aborting Requests
  • Runtime Compatibility
• Contributing

Installation

npm i -s @opengovsg/refx-ts-sdk

Reference

A full reference for this library is available here.

Usage

Instantiate and use the client with the following:

import { ReferralExchangeClient } from "@opengovsg/refx-ts-sdk";

const client = new ReferralExchangeClient({ apiKey: "YOUR_API_KEY" });
await client.referrals.upsert({
    patient: {
        uin: "uin",
        name: "name",
        phoneNumber: "91234567",
        dob: "1990-01-01",
        gender: "Male",
    },
    offeringId: "offeringId",
    senderHciCode: "senderHciCode",
    senderInstitutionName: "senderInstitutionName",
    doctorMcr: "doctorMcr",
    doctorName: "doctorName",
    doctorEmail: "doctorEmail",
    doctorContactNumber: "doctorContactNumber",
    isSubsidised: true,
    isUrgent: true,
    isDraft: true,
    formResponses: [
        {
            question: "question",
            id: "id",
            answer: "answer",
        },
    ],
});

Request and Response Types

The SDK exports all request and response types as TypeScript interfaces. Simply import them with the following namespace:

import { ReferralExchange } from "@opengovsg/refx-ts-sdk";

const request: ReferralExchange.EligibilityGetRequest = {
    ...
};

Exception Handling

When the API returns a non-success status code (4xx or 5xx response), a subclass of the following error will be thrown.

import { ReferralExchangeError } from "@opengovsg/refx-ts-sdk";

try {
    await client.referrals.upsert(...);
} catch (err) {
    if (err instanceof ReferralExchangeError) {
        console.log(err.statusCode);
        console.log(err.message);
        console.log(err.body);
    }
}

Advanced

Additional Headers

If you would like to send additional headers as part of the request, use the headers request option.

const response = await client.referrals.upsert(..., {
    headers: {
        'X-Custom-Header': 'custom value'
    }
});

Retries

The SDK is instrumented with automatic retries with exponential backoff. A request will be retried as long as the request is deemed retryable and the number of retry attempts has not grown larger than the configured retry limit (default: 2).

A request is deemed retryable when any of the following HTTP status codes is returned:

• 408 (Timeout)
• 429 (Too Many Requests)
• 5XX (Internal Server Errors)

Use the maxRetries request option to configure this behavior.

const response = await client.referrals.upsert(..., {
    maxRetries: 0 // override maxRetries at the request level
});

Timeouts

The SDK defaults to a 60 second timeout. Use the timeoutInSeconds option to configure this behavior.

const response = await client.referrals.upsert(..., {
    timeoutInSeconds: 30 // override timeout to 30s
});

Aborting Requests

The SDK allows users to abort requests at any point by passing in an abort signal.

const controller = new AbortController();
const response = await client.referrals.upsert(..., {
    abortSignal: controller.signal
});
controller.abort(); // aborts the request

Runtime Compatibility

The SDK defaults to node-fetch but will use the global fetch client if present. The SDK works in the following runtimes:

• Node.js 18+
• Vercel
• Cloudflare Workers
• Deno v1.25+
• Bun 1.0+
• React Native

Customizing Fetch Client

The SDK provides a way for your to customize the underlying HTTP client / Fetch function. If you're running in an unsupported environment, this provides a way for you to break glass and ensure the SDK works.

import { ReferralExchangeClient } from "@opengovsg/refx-ts-sdk";

const client = new ReferralExchangeClient({
    ...
    fetcher: // provide your implementation here
});

JWT Authenticated Client

If you need to authenticate requests by signing short-lived JWTs locally, use the ReferralExchangeJwtClient. It accepts a PEM-encoded ES256 private key and the API key name to embed as the issuer claim. By default each request receives a freshly signed token (15 second TTL) in the Authorization header, but you can opt into caching with a refresh buffer to reuse tokens safely. When opting in, you must supply the refresh buffer explicitly so the SDK knows how early to rotate tokens.

import { ReferralExchangeJwtClient } from "@opengovsg/refx-ts-sdk";

const client = new ReferralExchangeJwtClient({
    privateKey: process.env.REFX_PRIVATE_KEY!,
    apiKeyName: process.env.REFX_API_KEY_NAME!,
    environment: "Production", // or pass baseUrl
    tokenCache: {
        // The refresh buffer (required when enabling caching) is how much time must remain
        // before we stop reusing a JWT so requests don't arrive after the token's exp timestamp.
        refreshBufferSeconds: 5,
    },
});

const offerings = await client.offerings.list();

Omit the tokenCache block (the default) to sign a new token for every request. When you opt in, you must specify refreshBufferSeconds to control how early the SDK rotates tokens.

Contributing

While we value open-source contributions to this SDK, this library is generated programmatically. Additions made directly to this library would have to be moved over to our generation code, otherwise they would be overwritten upon the next generated release. Feel free to open a PR as a proof of concept, but know that we will not be able to merge it as-is. We suggest opening an issue first to discuss with us!

On the other hand, contributions to the README are always very welcome!